The present invention relates to automatic control of plastic flow through injection nozzles in a molding machine. More particularly the invention relates to proportional control of plastic flow via proportional control of the actuator mechanism for a valve for a nozzle particularly where two or more nozzles are mounted on a hotrunner for injection into one or more mold cavities. The proportional control is achieved via the use of one or more sensors which senses a selected condition of the plastic flow through a manifold, nozzle or into a mold and the use of the recorded condition in conjunction with a selected nozzle design, hotrunner/manifold design, actuator design, actuator drive mechanism and/or flow control mechanism. Proportional control of melt flow typically refers to control of the rate of melt flow according to an algorithm utilizing a value defined by a sensed condition as a variable.